10/16/2014 Aut ex - 4. Understandi ng Acoustics ht tp: //aut ex.com.au/ Techni cal -Gui des/ Qui etspace-Design-Gui de/4.-Understanding-Acoust i cs 1/6 HOME ABOUT US PRODUCT RANGE TECHNI CAL GUIDES ENVIRONMENTAL In buildings , acoustic treatment is add ed to reduce the impact of so und entering into sp ecific are as. Sound is controlled by t hree means : Firstly treatment of the source (e.g. building an enclosure aroun d the source such as around compress ors, or adding acous tic tr eatment to the area where th e sound is coming fr om) Secondly t reatment of the path o f the nois e (e.g. erection of barri ers such as building walls on freeways) And finally treatment at the receiver end. (e.g. weari ng earp lugs ) There aretwo types of acoustic functions that are of concern inthe building industry ; sound insula ti on and sound absorption. The acoustictreatments discussed in this manual are focused on sound absorption. Autex has cre ated acoustic treatments that reduce the levels of noise rev erberation within interiorenvironments by absorption of the sound. Sound is d efined as a source of energy; Sound absorption is the ability of a material to transform acoustical energy int o som e other form or energy, usuall y heat. All materials absorb s ome acous tical energy , some materials s uch as pla sterboard reflect most of the energy that strikes it, whereas other materials s uch as polyester insulation will abs orb mos t of the energy. The decimal fraction of the sound energy absorbed and n ot reflect ed by a material is termed sound absorption coefficient. As materia ls ab sorb d ifferent amounts o f sound e nergy at different frequenci es, s ound a bso rption coeffic ients are measu red at onethird octav e band centre fr equencies from 125 to 40 00 Hz. Building m aterials are ge nerally rat ed by their Noise Red uction Coefficient (NRC). To be an effectiv e sou nd abs orber, a material m ust have interconnecting air pockets or cells. Polyesterinsulation i s a very good s ound abs orber because it has many interconnect ing air pockets. Common Noise Reverberation terms Absorption : The changin g of energy to heat which red uces the a mou nt of energy which can be refl ected. Absorption C oefficien t: The amoun t of sound e nergy which is a bso rbed at any surface, this can vary with frequency and the angle at which the s ound hits s urface. Hertz (Hz): Frequency of sound. The same as Cycles Per Second. KHz: Frequency in thousands e.g. 1 KHz = 1000Hz Noise Red uction (NR): The difference in sound press ure level between any two points along the pa th ofTechnical Guides: Residential I nsu lation Design Guide Commercial Acoustic Design Guide Mechanical Services Insulation Guide Quietspace® Design Guide 1. Why Polyester? 2. Env ironmental Cons iderations 3. Why consider Ac oustics? 4. Und ersta ndin g Acoustics 5. Autex Quietspace Acoustic Products 6. Quietspace in Education 7. Quietspace in Offices 8. Quietspace Versatility 9. Quietspace Resid ential 10. Quietspace Product Estimator11. Quietspace Working Examples SELECT ACOUNTRY: AUSTRALIA NEW Z EALAND CONTACT US 4. Understa nding Acoustic s
